IETF test cases - 1 of 64 FAIL (63 of 64 PASS) in frame.TestFrameHash (decoding audio samples)

[mewmew]

This issue is a follow-up on #54 (which handles FLAC stream decoding). In particular, this issue handles issues of FLAC audio sample decoding (e.g. mismatch between expected audio samples and decoded audio samples).

The IETF flac-test-files repository contains 64 FLAC files, published by @ktmf01, which help exercise corner cases of the FLAC decoder.

When adding these test cases to the test suite, 7 of 64 FLAC files resulted in audio sample decoding failures, namely:

    --- FAIL: TestFrameHash/../testdata/flac-test-files/subset/16_-_partition_order_8_containing_escaped_partitions.flac (0.05s)
    --- FAIL: TestFrameHash/../testdata/flac-test-files/subset/22_-_12_bit_per_sample.flac (3.24s)
    --- FAIL: TestFrameHash/../testdata/flac-test-files/subset/32_-_high_resolution_audio,_partition_order_8_containing_escaped_partitions.flac (0.14s)
    --- FAIL: TestFrameHash/../testdata/flac-test-files/subset/37_-_20_bit_per_sample.flac (11.43s)
    --- FAIL: TestFrameHash/../testdata/flac-test-files/subset/62_-_predictor_overflow_check,_20-bit.flac (1.63s)
    --- FAIL: TestFrameHash/../testdata/flac-test-files/subset/63_-_predictor_overflow_check,_24-bit.flac (0.01s)
    --- FAIL: TestFrameHash/../testdata/flac-test-files/subset/64_-_rice_partitions_with_escape_code_zero.flac (0.01s)

This issue tracks the resolution of the identified decoding issues.

• 16_-_partition_order_8_containing_escaped_partitions.flac
• 22_-_12_bit_per_sample.flac
• 32_-_high_resolution_audio,_partition_order_8_containing_escaped_partitions.flac
• 37_-_20_bit_per_sample.flac
• 62_-_predictor_overflow_check,_20-bit.flac
• 63_-_predictor_overflow_check,_24-bit.flac
• 64_-_rice_partitions_with_escape_code_zero.flac

To reproduce, run:

go test -v github.com/mewkiz/flac/frame

Remember to initiate the submodule for IETF test cases in the testdata/flac-test-files directory:

git submodule update --init --recursive

[mewmew]

MD5 mismatches for decoded audio samples:

=== FAIL   TestFrameHash/../testdata/flac-test-files/subset/16_-_partition_order_8_containing_escaped_partitions.flac
MD5 checksum mismatch for decoded audio samples; expected d0e1313950dc04b749c53cd349251bed, got 1d1380204d7eb5b138fe884178e9b67d

=== FAIL   TestFrameHash/../testdata/flac-test-files/subset/32_-_high_resolution_audio,_partition_order_8_containing_escaped_partitions.flac
MD5 checksum mismatch for decoded audio samples; expected 88c57117179b46e784643de9f20c1917, got b7377fd70228aed730cbb00e55dbafab

=== FAIL   TestFrameHash/../testdata/flac-test-files/subset/63_-_predictor_overflow_check,_24-bit.flac
MD5 checksum mismatch for decoded audio samples; expected e4e4a6b3a672a849a3e2157c11ad23c6, got a0343afaaaa6229266d78ccf3175eb8d

=== FAIL   TestFrameHash/../testdata/flac-test-files/subset/64_-_rice_partitions_with_escape_code_zero.flac
MD5 checksum mismatch for decoded audio samples; expected 0885019a14d23a6759404c96f525a9d4, got ef5f7a4d27bd066acf31c7a68d5758df

[mewmew]

mewkiz/flac audio samples for IETF test case subset/16 - ...flac

FLAC reference audio samples for IETF test case subset/16 - ...flac

[mewmew]

The last remaining test case that's failing is 63 - predictor overflow check, 24-bit.flac.

mewkiz/flac audio samples for IETF test case subset/63 - ...flac

FLAC reference audio samples for IETF test case subset/63 - ...flac

From the IETF test case README:

• File 61, 62 and 63 are signals with rather extreme
  characteristics that might trigger overflow if a decoder
  uses 32-bit integers to calculate the predictor where 64-bit
  integers are appropriate

[mewmew]

Fixed by @MarkKremer in #61.

[mewmew]

(from: #61 (comment))

The v1.0.9 release has now been tagged.

Very happy to see that the audio samples of the IETF test cases are now correctly decoded by mewkiz/flac.

Cheerful regards,
Henry & Robin